Genome complexity: RNA gene activity controls (Introduction)

by David Turell @, Monday, February 03, 2020, 21:33 (1515 days ago) @ David Turell

A very specialized cellular system to remove damaged RNA due to misfolding and other causes:

https://phys.org/news/2020-02-fundamental-discovery-gene.html

"Researchers at Johns Hopkins Bloomberg School of Public Health have discovered a fundamental mechanism that regulates gene activity in cells. The newly discovered mechanism targets RNA, or ribonucleic acid, a close cousin of DNA that plays an important role in cellular activity.

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"The newly discovered mechanism effectively silences or dials down certain active genes as a basic cellular regulatory or quality-control system. It may even act as a defense against viruses. When genes are active, they are copied out into strands of RNA. These RNA strands perform cellular functions on their own or are translated into proteins. The new mechanism destroys RNA strands that have excessively folded over and stuck to themselves to form knots, hairpins, and other structures. These highly structured RNAs can occur during normal processing but could possibly also be caused by misfolding.

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"Most of the regulatory and quality-control mechanisms that modulate the levels of RNAs in cells target RNAs containing specific sequences of nucleotides—the building blocks of RNAs. The newly discovered mechanism is unique in that it recognizes not sequences but a broad variety of structures formed where RNA strands, which are relatively sticky, have folded back onto themselves.

"Leung and his team discovered the new mechanism while investigating a protein called UPF1, which is known to work in other RNA regulation pathways. They found that UPF1 and a partner protein called G3BP1 work together in the new mechanism, targeting only RNAs that contain a high level of structures. When the researchers depleted UPF1 or G3BP1 from cells to shut off the new mechanism, levels of highly structured RNAs rose sharply. The team also confirmed that the new mechanism, which they call structure-mediated RNA decay, is distinct from all other known RNA-removal mechanisms and works across different types of RNA throughout the genome.

"'Based on further analyses, we predict that this structure-mediated RNA decay pathway could regulate at least one-fourth of human protein-coding genes and one-third of a class of non-coding genes called circular RNA," Leung says."

Comment: Cells are constantly reproducing themselves so life has to be designed to correct genome mistakes and this is such a required complex design.


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